In the conventional color halftone picture, or, ofr example, in a color television picture, a continuous family of colors is simulated by the superposition or complementary juxtaposition of three "single color" halftones or "separations". These three colors are often referred to as the three "primaries". For example, there may be a "red" separation, a "blue" separation, and a "green" separation.
In magazine or color print lithography, different primary color dots are deposited on the paper or other medium in various sizes or diameters, so that the human eye integrates these dots and interprets them as various colors depending upon the dot mix. In photography, color negatives are provided which detect the various colors passing through the lens in a reversal process and, when printed, the various colors become viewable by the human eye. In all of these instances, however, the color perceived is due to either the reflective, transmissive, absorptive and/or radiant properties of the media (e.g., toners, inks, dyes, phosphors, pigments, etc.) involved, not the dispersive or diffractive properties.
A co-pending application, Ser. No. 846,523, by the same inventor and to the same assignee, discloses that a full color image is created and is viewable in white light without the aid of colored inks, toners, sources, guns, or phosphors. A full color reproduction of a color picture, image or scene is realized by means of diffraction techniques. The output reproduction consists of a regular array of small planar diffraction gratings of multiple spatial frequencies configured in much the same way as conventional color halftone dots or color television pixels. Each individual grating by itself would produce a relatively monochromatic color sensation. A multiplicity of gratings are then superimposed or co-mingled in such a way as to produce any arbitrary color sensation. (In Ser. No. 846,523, no opaquing techniques are used and new separation masks and a new master must be created for each new original.)
In accordance with the present application, a sheet of reflective or transmissive multiple diffraction gratings (which will appear much as a plain white canvas or paper) is prepared as in said copending application, with, however, no predisposition as for a particular image to be reproduced. The multiple reflective diffraction pixels are then selectively masked by, for example, black marks applied by xerographic or photographic means. The canvas is blackened or opaqued or rendered non-diffracting in such a way as to leave the appropriate grating or portion thereof exposed and functional for the correct color reproduction on a pixel-by-pixel basis.